Preparation And Drug Loading Properties Study Of MPDA Core Shell Micro/Nano Carriers

In this paper,two kinds of core-shell drug carriers were prepared by using mesoporous polydopamine（MPDA）with excellent biosafety and mesoporous structure as shell.One was hollow mesoporous particles with Fe₃O₄as the core and MPDA as the shell（Fe₃O₄@HMPDA）.The other was a composite core-shell nanoparticles using SiO₂particles with fluorescein isothiocyanate（FITC）inside as the core,and using MPDA with Au nanoparticles（Au NPs）grafted on the outer layer as the shell（F-SiO₂@MPDA-Au NPs）.The main control factors of the construction process of two nano-medicine carrier structures were discussed,and the adsorption performance of Fe₃O₄@HMPDA particles for dyes and anticancer drug doxorubicin hydrochloride（DOX）,and the sustained release performance under different p H values were investigated.The performance of F-SiO₂@MPDA-Au NPs nanoparticles,such as fluorescence performance,photothermal performance,adsorption performance,and sustained release performance were also be discussed.The main research contents are as follows:1.Preparation and performance of Fe₃O₄@HMPDA nanoparticlesFirst,Fe₃O₄ nanoparticles with a particle size of about 200 nm were synthesized by a solvothermal method,and then Fe₃O₄@SiO₂particles were synthesized by St（?）ber method under the action of 3-aminopropyltriethoxysilane（APTES）.Subsequently,pluronic F127 and1,3,5-Trimethylbenzene（TMB）were used as a templating agent to construct MPDA layer on the surface of Fe₃O₄@SiO₂particles to obtain Fe₃O₄@SiO₂@MPDA nanoparticles.Finally,SiO₂is removed by etching with NaOH solution to obtain Fe₃O₄@HMPDA hollow mesoporous core shell nanoparticles.Transmission electron microscope（TEM）and field emission scanning electron microscope（FESEM）were used to observe the morphology of particles,X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）,Zeta potential,N₂ adsorption-desorption,vibration sample magnetometer（VSM）and so on were used to study the composition,magnetic properties,specific surface area and pore volume of samples.Then,through the carrier’s adsorption experiment for dyes and drugs,the sustained release performance under different p H values,the cytotoxicity test（MTT method）,etc.,the drug delivery and sustained release performance,and the inhibitory effect of drug loaded vector on normal cells and cancer cells were studied.The results show that the drug carrier has a large drug carrying capacity（168.7 mg/g）and p H response release performance,and a strong inhibitory effect on cancer cells.2.Preparation and performance of F-SiO₂@MPDA-Au NPs composite nanoparticlesFirst,FITC and APTES were combined to obtain FITC-APS solution,and then FITC-APS was embedded in SiO₂nanoparticles by reverse microemulsion method to obtain F-SiO₂particles.And then the MPDA layer was also constructed on the surface of F-SiO₂particles to obtain the F-SiO₂@MPDA nanoparticles.Finally,Au NPs were grafted on the surface of F-SiO₂@MPDA particles by citrate reduction method to obtain F-SiO₂@MPDA-Au NPs composite nanoparticles.TEM and FESEM were used to observe the morphology of particles;XPS was used to study the composition of composite materials;fluorescence spectroscopy,N₂adsorption-desorption experiment and photothermal experiments were used to study the fluorescence properties,pore structure and photothermal properties of the composite particles;UV spectroscopy was used to study the adsorption and slow-release performance of the carrier for dye and DOX.The results showed that F-SiO₂@MPDA-Au NPs nanoparticles have good fluorescence performance,large drug loading（111.275mg/g）,good photothermal performance（36.95%）,which were useful in bioimaging and it has potential application in cancer treatment.MPDA with mesoporous structure not only has good biosafety,but also improves the delivery capacity of drug carriers and provides channels.The electrostatic attraction between MPDA and drug also makes it have a p H-responsive slow-release function.The hollow structure of Fe₃O₄@HMPDA particles could also improve drug loading capacity,and Fe₃O₄could endow the carrier with magnetic targeting.The drug can be transported to specific organs or tissues by external magnetic field,which can improve the utilization rate of drugs.The FITC in F-SiO₂@MPDA-Au NPs composite nanoparticles makes it have fluorescent imaging function.Both of PDA and Au NPs have photothermal properties,they can use the heat sensitivity of cancer cells to kill cancer cells,so as to achieve the purpose of targeted treatment.